Hiep T. Nguyen

Laparoscopic linear cutting stapler failure

OBJECTIVESnTo characterize the frequency and nature of problems with linear cutting staplers to help prevent complications in the future. These devices are often used during laparoscopic urologic procedures.nnnMETHODSnWe retrospectively reviewed the experience with laparoscopic linear cutting staplers at two institutions routinely performing urologic laparoscopy and analyzed the difficulties with any staplers. Data from the Food and Drug Administration Center for Devices and Radiological Health were also examined to determine the prevalence and types of reported problems.nnnRESULTSnIn performing approximately 460 laparoscopic cases, we encountered 5 problems (1%) with endovascular gastrointestinal anastomosis staplers. Fifty-five additional cases in 50 patients were documented in the Food and Drug Administration database. Of the 55 patients, 15 (27%) required open conversion to manage the problem, 8 (15%) received blood transfusions, and 2 (4%) died postoperatively. Twenty-two events occurred during 19 laparoscopic donor nephrectomies (35%) without associated graft dysfunction, damage, or loss. All phases of instrument use were subject to problems; however, abnormal firing of the stapler and improper staple formation were the most common and morbid aspects of device malfunction.nnnCONCLUSIONSnDespite the general reliability of linear cutting staplers, difficulties were encountered in every step of use. Most situations were successfully managed by prompt identification and appropriate intracorporeal maneuvers. Nevertheless, significant morbidity may occur, and conversion to an open operation should be considered. Many potential problems can be avoided by surgeon and staff education, and one should be aware of the alternative methods of tissue ligation currently available.

FETAL INTERVENTION FOR MYELOMENINGOCELE: EFFECT ON POSTNATAL BLADDER FUNCTION

PURPOSEnMyelomeningocele is the most common congenital malformation of the central nervous system noted on prenatal ultrasound. Due to its significant postnatal sequelae, treatment in utero could potentially have a profound impact on the newborn. Others have reported fetal surgical techniques for in utero repair of myelomeningocele and its potential benefits on motor and neurological function. We report our urodynamic findings in the newborn after in utero repair of spina bifida in an effort to characterize postnatal bladder function.nnnMATERIALS AND METHODSnA retrospective review of the fetal surgery database at University of California San Francisco was performed identifying patients with a diagnosis of myelomeningocele. Prenatal surgical repair of myelomeningocele was considered if a normal karyotype was present, no other significant congenital anomalies were evident and gestational age was less than 24 weeks. The spinal defects were in the lumbar or lumbosacral region. All surgery was performed before 24 weeks of gestations.nnnRESULTSnFetal surgery to correct myelomeningocele was performed in 6 patients. All patients were born premature at 32 weeks of gestation or less. Videourodynamics performed at age 1 month in 4 patients indicated decreased bladder capacity for weight, increased detrusor storage pressures and significant post-void residual. Hydronephrosis was demonstrated in 4 patients on renal/bladder ultrasound, and moderate vesicoureteral reflux was seen in 3.nnnCONCLUSIONSnPatients with spinal bifida treated in utero appear to have the same changes in urodynamic parameters and anatomical abnormalities in the urinary tract as other children with spinal defects who have undergone standard postnatal care. In utero treatment of spinal bifida may expose the newborn to the effects of prematurity. The long-term effects on bladder function in the fetus after in utero repair of myelomeningocele remain unknown. A randomized controlled trial is necessary to evaluate long-term bladder function as well as other outcome variables in this experimental approach to patients with myelomeningocele.

Update of PAX2 mutations in renal coloboma syndrome and establishment of a locus-specific database

Renal coloboma syndrome, also known as papillorenal syndrome is an autosomal‐dominant disorder characterized by ocular and renal malformations. Mutations in the paired‐box gene, PAX2, have been identified in approximately half of individuals with classic findings of renal hypoplasia/dysplasia and abnormalities of the optic nerve. Prior to 2011, there was no actively maintained locus‐specific database (LSDB) cataloguing the extent of genetic variation in the PAX2 gene and phenotypic variation in individuals with renal coloboma syndrome. Review of published cases and the collective diagnostic experience of three laboratories in the United States, France, and New Zealand identified 55 unique mutations in 173 individuals from 86 families. The three clinical laboratories participating in this collaboration contributed 28 novel variations in 68 individuals in 33 families, which represent a 50% increase in the number of variations, patients, and families published in the medical literature. An LSDB was created using the Leiden Open Variation Database platform: www.lovd.nl/PAX2. The most common findings reported in this series were abnormal renal structure or function (92% of individuals), ophthalmological abnormalities (77% of individuals), and hearing loss (7% of individuals). Additional clinical findings and genetic counseling implications are discussed. Hum Mutat 33:457–466, 2012.

99mTechnetium dimercapto-succinic acid renal scintigraphy abnormalities in infants with sterile high grade vesicoureteral reflux

PURPOSEnAlthough vesicoureteral reflux associated with bacteriuria may cause renal scarring, sterile reflux is thought not to cause renal injury. We determined the incidence and associated characteristics of renal abnormalities using 99mtechnetium(Tc) dimercapto-succinic acid (DMSA) renal scintigraphy in infants with high grade vesicoureteral reflux but no history of urinary tract infection.nnnMATERIALS AND METHODSnWe retrospectively reviewed the results of 99mTc-DMSA renal scintigraphy and renal ultrasonography performed during the first 6 months of life in infants with vesicoureteral reflux detected during the postnatal evaluation of prenatal hydronephrosis or sibling reflux screening. Those with a history of urinary tract infection, or evidence of ureteropelvic junction or bladder outlet obstruction were excluded from study.nnnRESULTSnOf the 28 male and 6 female infants who met study criteria vesicoureteral reflux was bilateral in 25 and unilateral in 9. Reflux grade was IV or V, II or III and I in 38, 18 and 3 of the 59 refluxing renal units, respectively. 99mTc-DMSA renal scintigraphy revealed parenchymal abnormalities in 24 refluxing renal units (41%) in 22 patients (65%), of whom 19 (86%) were male and 15 (68%) had bilateral reflux. We noted differential uptake less than 40% with and without cortical defects in 10 and 7 refluxing units, respectively, and cortical defects only in 7. Of the 24 refluxing units with abnormalities 21 were associated with grade IV or V and 3 with grade II or III reflux. Ultrasound showed evidence of renal injury in only 7 of the 17 patients (41%) in whom 99mTc-DMSA scintigraphy was abnormal.nnnCONCLUSIONSnIn our study the majority of infants with high grade reflux had decreased differential function and/or cortical defects. Parenchymal defects detected by 99mTc-DMSA renal scintigraphy were often not identified by renal ultrasound. Therefore, 99mTc-DMSA renal scintigraphy is especially useful for initially evaluating infants with high grade, sterile vesicoureteral reflux.

Patterns and Predictors of Laparoscopic Complications in Pediatric Urology: The Role of Ongoing Surgical Volume and Access Techniques

PURPOSEnLaparoscopic surgery in children has evolved to include complex reconstructive procedures. While complication rates are low, they can have significant consequences. In this study we define the incidence and risk factors for complications in children undergoing laparoscopic urological surgery.nnnMATERIALS AND METHODSnWe conducted a retrospective analysis of all conventional and robot assisted laparoscopic urological procedures performed at our institution from 1995 to 2005. Complications were graded based on Claviens classification. Statistical analysis was performed using the t test and Fishers exact test.nnnRESULTSnA total of 806 laparoscopic procedures were evaluated. Overall, there was a 2% complication rate, including 1.6% for access related and 0.7% for procedural complications (in 440 nondiagnostic cases). Complications related to access occurred in 9 of 396 cases (2.3%) using Veress access, compared to 3 of 389 cases (0.8%) using open access (p = 0.14). The incidence of grades III and IV complications was identical between techniques (0.8%). Complications included preperitoneal insufflation sufficient to necessitate conversion to an open procedure (0.7%), vessel injury (0.4%), small bowel injury (0.4%), bleeding requiring conversion (0.1%), bladder perforation (0.1%) and vas deferens injury (0.2%). Surgeons performing more than 12 laparoscopic cases annually had a significantly lower complication rate (p = 0.024).nnnCONCLUSIONSnThe low risk of complications demonstrated in this series confirms that laparoscopic procedures are safe, although there remains a risk of significant injury. Determinants of surgical outcome include laparoscopic activity, and to a lesser extent access technique. Most if not all complications are preventable with proper adherence to technique and ongoing education.

JNK/SAPK and p38 SAPK-2 Mediate Mechanical Stretch-Induced Apoptosis via Caspase-3 and -9 in NRK-52E Renal Epithelial Cells

Background/Aims: In renal epithelial cells, mechanical forces produced from urinary obstruction serve as potential mediators of apoptosis by activating specific intracellular signaling pathways. In this study, we sought to further define the role of JNK and p38 SAPK-2 pathway and caspase activation in stretch-induced apoptosis. Methods: Immortalized cell lines derived from the various components of the nephron were subjected to cyclical stretch and their differential apoptotic response was assessed. Pharmacologic inhibitors and Western blot analysis were used to assess the involvement of the MAPK pathways. Caspases’ activity was assessed with ELISA and by Western blot analysis. Results: Stretch-induced apoptosis was dependent upon the cell phenotype and the degree of stretch. In NRK-52E cells, it was mediated through both JNK and p38 SAPK-2 pathways, and inhibition of either pathway reduced the degree of stretch-induced apoptosis. Stretched cells showed increased activity of caspase-3 and -9 but not -2 or -8. Stretch-induced apoptosis was modulated by inhibition of caspase-3 and to a lesser extent by caspase-9. Conclusion: These findings suggest that stretch induces apoptosis in renal epithelial cells through the specific activation of JNK/SAPK and p38 SAPK-2 pathways and is dependent on the activation of caspase-3 and -9.

Current management of antenatal hydronephrosis

The strategy for the management of children with urinary tract anomalies has changed considerably as a result of the development of ultrasound equipment and techniques that allow for detailed fetal evaluation. Hydronephrosis is the most common urogenital anomaly detected, suggesting that an obstructive process may be potentially present. The goal of postnatal management is to identify and treat those patients whose renal function is at risk, while leaving alone the high percentage of patients who are at no risk of renal damage. This management involves a spectrum of radiological, medical, and surgical interventions for diagnosis, surveillance, and treatment. In this article, we review our current understanding of the natural history of antenatal hydronephrosis and its management.

Normal Human Ejaculatory Duct Anatomy: A Study of Cadaveric and Surgical Specimens

PURPOSEnW examined the anatomy of the ejaculatory ducts in normal men and correlated findings with theories of ejaculatory duct obstruction.nnnMATERIALS AND METHODSnGross and microscopic anatomical studies were performed on cadaveric and operative specimens derived from radical prostatectomy.nnnRESULTSnHistologically, the ejaculatory ducts are a continuation of the seminal vesicles. However, the thick muscle wall of the seminal vesicle is not present within the ejaculatory duct. Normal ejaculatory duct luminal and wall dimensions are remarkably uniform among men. A luminal diameter of greater than 2.3 mm. defines a dilated system statistically.nnnCONCLUSIONSnThe largely collagenous ejaculatory ducts may serve as simple semen conduits instead of muscular tubes with spasmodic, sphincteric or peristaltic properties. The anatomical findings presented suggest several possible mechanisms for the prevention of urinary reflux into the ejaculatory ducts.

Changing the Technique of Background Subtraction Alters Calculated Renal Function on Pediatric Mercaptoacetyltriglycine Renography

PURPOSEnAlthough many operative decisions are based on apparent changes in function detected by serial diuretic renography, the reliability of relative renal function data has been questioned. We investigated the effect of background subtraction on calculated renal function.nnnMATERIALS AND METHODSnWe reviewed 23 pediatric mercaptoacetyltriglycine renograms. Regions of interest for background subtraction were redrawn and relative renal function values were recalculated.nnnRESULTSnIn patients with left hydronephrosis left differential renal function was consistently underestimated by 7.3% compared to the superior and 4.7% compared to the average background subtraction technique. In patients with right hydronephrosis, when considering lower pole background activity only, right differential renal function was consistently overestimated by 15.8% compared to the superior and 2.4% compared to the average background subtraction technique. In patients younger than 1 year at the time of study these differences were exaggerated.nnnCONCLUSIONSnBecause of overlapping hepatic background activity, the position of regions of interest for background subtraction may greatly influence calculated renal function. We recommend that the preferred method of calculating background subtraction to minimize error be based on a region of interest surrounding the whole kidney. This method is especially pertinent in patients with right hydronephrosis and in those younger than 1 year. Reported relative renal function data should be interpreted with caution.

Rectus fascial sling for the treatment of neurogenic sphincteric incontinence in boys : Is it safe and effective?

PURPOSEnWhile a fascial sling for treating children with intractable urinary incontinence is often successful in girls, its effectiveness in boys remains unclear. We determined the long-term efficacy of a rectus fascial sling in boys with neurogenic sphincteric incontinence and defined its urodynamic characteristics for achieving continence.nnnMETHODS AND METHODSnWe reviewed the charts of all boys who underwent a rectus fascial sling procedure for neurogenic incontinence to determine urinary continence status at the most recent office visit or by telephone interview, the type and dose of anticholinergic and sympathomimetic medications, the frequency of intermittent clean intermittent catheterization, status of the upper urinary tract and comparative urodynamic findings preoperatively and postoperatively.nnnRESULTSnWe evaluated 7 boys 7 to 19 years old, of whom 4 were postpubertal, who fulfilled study criteria and had a followup of 1 to 9 years. In 4 patients a continent stoma was created concurrently at surgery. Postoperatively all patients were dry during the first 3 months after surgery. At the last followup 1 patient was completely dry, 3 had occasional nighttime wetting, 2 had occasional stress incontinence, and 1 had frequent daytime and nighttime wetting requiring subsequent bladder neck closure. Prepubertal and postpubertal males performed catheterization without difficulty and all required less frequent clean intermittent catheterization and medication postoperatively compared to preoperative status. None had hydronephrosis. Postoperatively urodynamic evaluation revealed normal bladder compliance, improved urethral resistance that did not decay with bladder filling and no uninhibited contractions.nnnCONCLUSIONSnThe rectus fascial sling is effective for increasing bladder outlet resistance and decreasing the degree of incontinence in prepubertal and postpubertal males with neurogenic sphincteric incontinence. It has no long-term deleterious effects on bladder function and does not impair the ability to catheterize postoperatively. A fascial sling is an effective alternative to bladder neck closure when creating a continent stoma.